Model Output Discussion - cold spell to end Autumn

[Captain Shortwave]

GFS going for another cut off high somewhere to our north/north west. Low pressure south of Greeland digging south east as well as another pulse of cold air ejecting towards Scandinavia which squeezes the Atlantic ridge leaving the remaining warm air in situ close to Iceland. We will need to see other models come around to this idea first but at least the initial northerly looks fairly solid.

[northwestsnow]

GFS is really nice- jet sinking south...LP into Europe...all good.

[feb1991blizzard]

The UKMO doesn't deliver any backedge snow on Thursday, this map here is based on the UKMO I think and you can zoom in and there just isn't any.

https://www.metoffice.gov.uk/public/weather/forecast/map/gcpvj04sd#?map=SignificantWeather&fcTime=1512615600&zoom=9&lon=-1.28&lat=54.12

[knocker]

Classic chart illustrating the trough to the east and the energy flows including the Strong jet

 

Edited December 2, 2017 by knocker

[Derecho]

Bitterly cold GFS as I can imagine a lot of places could have some snow from that northerly... then we get slack winds with cold uppers over the snowfields.

[Nick F]

Interesting on the 12z GFS how the secondary lows dropping SE from S Greenland are forced away from the UK down the far west by the deep CAA wrapping around the cold vortex over Norway, keeping those mild sectors at bay to the west. This keeps the UK in a more protracted cold spell, maybe with a potential snow event in the west where these secondary lows interact with the CAA.

Edited December 2, 2017 by Nick F

[karlos1983]

7 minutes ago, feb1991blizzard said:

The UKMO doesn't deliver any backedge snow on Thursday, this map here is based on the UKMO I think and you can zoom in and there just isn't any.

https://www.metoffice.gov.uk/public/weather/forecast/map/gcpvj04sd#?map=SignificantWeather&fcTime=1512615600&zoom=9&lon=-1.28&lat=54.12

Still delivers some frigid air and plenty of showers of a wintry variety 

[N/A]

1 hour ago, Draig Goch said:

Much more agreement in the colder runs on the GEFS 6z for Porthcawl South Wales. Top photo is yesterday, bottom is today. There's still hopes!! 

Wow look at that 850mb temperature fall off a cliff, mind you that isn't the only thing to fall as my yoghurt just fell out of my hand seeing that, luckily the lid is still on! Right I'm off now to book a b&b in Porthcawl  because I'm not sure Tenby will be the same

[Iceberg]

3 minutes ago, Nick F said:

Interesting on the 12z GFS how the secondary lows dropping SE from S Greenland are forced away from the UK down the far west by the deep CAA wrapping around the cold vortex over Norway, keeping those mild sectors at bay to the west. This keeps the UK in a more protracted cold spell, maybe with a potential snow event in the west where these secondary lows interact with the CAA.

Was just about to mention this the filling of the lows from t180 just south of Greenland are anti norm as well. This kind of movement should indicate scandy high pressure but gfs wasn’t playing ball this run. Tbh gfs seemed a little clueless what to do t180 onwards.

[Backtrack]

Models looks fantastic at face value. Clear to see that Exeter aren’t onboard yet though, reflected in their text forecasts for a 24hr cold-shot before milder air replaces it. 

All eyes down for ECM

[IDO]

GEM continues to follow its mean with a 24 hour toppler late next week and zonal going forward based on an Azores high. 

Would not put much faith in that normally, but a carbon copy of ECM 0z, so concerning. 

Something will have to give soon so no point worrying about snow chances Thursday/Friday till we get the cross-model agreement on the Atlantic Block/wedge synoptic.

[Chesil View]

1 minute ago, Backtrack said:

Models looks fantastic at face value. Clear to see that Exeter aren’t onboard yet though, reflected in their text forecasts for a 24hr cold-shot before milder air replaces it. 

All eyes down for ECM

Try reading the the 6 to 30 day outlook updated today. Its wintry through till the end of the month.

[terrier]

I want to believe in the gfs this time but unfortunately the way it performs in the stats tells you everything you need to know. Think most places will be more wet than white. Would be interesting to see the ukmo 168 chart. Because I think we are going to see a brief northerly shot at end of week before Atlantic moves back in. Think ecm will be on the money. And it seems the met are edging towards the ecm output from there updates 

[ACCOUNT DELETED]

4 minutes ago, Dafydd Tomos said:

Wow look at that 850mb temperature fall off a cliff, mind you that isn't the only thing to fall as my yoghurt just fell out of my hand seeing that, luckily the lid is still on! Right I'm off now to book a b&b in Porthcawl  because I'm not sure Tenby will be the same

Wait a minute! Pembroke GEFS are the same! You might not have to even leave Tenby. Can't get the GEFS for Tenby itself though which is strange when many other towns are on there.  

[Djdazzle]

1 minute ago, terrier said:

I want to believe in the gfs this time but unfortunately the way it performs in the stats tells you everything you need to know. Think most places will be more wet than white. Would be interesting to see the ukmo 168 chart. Because I think we are going to see a brief northerly shot at end of week before Atlantic moves back in. Think ecm will be on the money. And it seems the met are edging towards the ecm output from there updates 

ECM hasn’t come out yet . . .

[Mucka]

When GFS deep FI is showing 1055mb Polar high's there is no reason tot hink typical zonal conditions will return anytime soon in December.

[Ice Day]

Well another duo of good/very good runs from UKMO and GFS.  Both showing a pretty potent northerly at 144/

  

I would gladly take either of them, although GFS has slightly better heights up towards Greenland and looks like it would have better longevity.  This is terrific model watching at the moment.....and it's only the 2nd December!!!

[karyo]

7 minutes ago, IDO said:

GEM continues to follow its mean with a 24 hour toppler late next week and zonal going forward based on an Azores high. 

Would not put much faith in that normally, but a carbon copy of ECM 0z, so concerning. 

Something will have to give soon so no point worrying about snow chances Thursday/Friday till we get the cross-model agreement on the Atlantic Block/wedge synoptic.

This is worrying! It will feel like a long wait till the ECM comes out.

[igloo]

3 minutes ago, terrier said:

I want to believe in the gfs this time but unfortunately the way it performs in the stats tells you everything you need to know. Think most places will be more wet than white. Would be interesting to see the ukmo 168 chart. Because I think we are going to see a brief northerly shot at end of week before Atlantic moves back in. Think ecm will be on the money. And it seems the met are edging towards the ecm output from there updates 

im not sure the met goes along those lines colder than average and wintry for northern areas to the end of the month but i have to say they do change on a daily basis 

[Sawel]

25 minutes ago, feb1991blizzard said:

The UKMO doesn't deliver any backedge snow on Thursday, this map here is based on the UKMO I think and you can zoom in and there just isn't any.

https://www.metoffice.gov.uk/public/weather/forecast/map/gcpvj04sd#?map=SignificantWeather&fcTime=1512615600&zoom=9&lon=-1.28&lat=54.12

Those maps (and forecasts for the next 7 days) are based on the MOGREPS ensembles and not the UKMO run.

Edited December 2, 2017 by Sawel

[SLEETY]

Gfs pushing the atalantic through as soon as it hits low res again .Every time it seem to do that 

[terrier]

So the gem follows the ecm of this morning with a brief northerly at end of week. Why do I get the feeling the gfs is leading us up the garden path again. 

[SMU]

^^ so your just ignoring the UKMET^^

[Chesil View]

3 minutes ago, terrier said:

So the gem follows the ecm of this morning with a brief northerly at end of week. Why do I get the feeling the gfs is leading us up the garden path again. 

To be honest the ECM has also held the garden path trophy over the last couple of winters.

[northwestsnow]

3 minutes ago, Steve Murr said:

^^ so your just ignoring the UKMET^^

Well its all about opinions steve but i like ukmo 144 today- yes the high will topple but i think there is enough momentum in the trough pushing south to prevent a zonal reset..:)